In 1960, one of the oldest US helicopter companies, Piasecki Aircraft, initiated the Pathfinder program. From the very beginning, the 16H-1 prototype was created using a single-rotor scheme, with a tail rotor. The first flight took place on February 21, 1961. Less than a year later, a wing was installed on the 16N-1, as planned, and the RV was replaced with a three-bladed hood pusher propeller with controlled surfaces at the exit. The latter provided directional control and torque parry. During flight tests, a cruising speed of 273 km / h was achieved. After this, the military joined in financing the project with the condition of bringing the speed to 370 km / h. At the insistence of the military, a number of changes were made to the project, namely, lengthening the fuselage and increasing the payload, remotorization, replacing the main and pusher propellers, etc. The helicopter adopted the index 16H-1A or Pathfinder II. Significant acceleration was achieved by redistributing the input power from the NV to the pushing one. In this mode, the main lift was generated by the wing. The test results were encouraging - a speed of 361 km / h, good handling and maneuverability, both at high and low flight speeds. In the future, the company developed several modifications with different take-off weights, but not one of them even reached the prototype. The results of the research were applied by the military to create the AH-56A Cheyenne.
Piasecki continued theoretical work on the chosen scheme until 1978. A return to the former topic became obvious when, in the mid-90s, the military became interested in using Piasecki's developments to improve the performance of the AH-64 Apache and AH-1W SuperCobra. A large amount of work has been carried out, including full-scale modeling and a ground test cycle. Changes in the transmission of base helicopters, new control systems, etc. were required. But the result was a contract to modify the medium multipurpose UH-60 Black Hawk. After 3 years, the prototype adopted the X-49A Speedhawk index. The fundamental difference from 16N-1 was a different design for deflecting the air flow of the pushing rotor - they used a more efficient, composite hemisphere, which unfolds at 90 ° C at low speeds and hovering, and at high speeds of horizontal flight fits into the contour of the casing, thereby not experiencing loads and removing the vibration source of the tail boom. The Kh-49A made its 1st flight on June 29, 2007.
In 2008, Piasecki Aircraft received funds to finalize and conduct the second phase of flight tests of the experimental X-49A helicopter. It should be noted that after the completion of the first stage of flight tests, the future prospects of the X-49A SpeedHawk remained unclear. Moreover, the funding provided also does not solve all the problems, since, according to representatives of Piasecki Aircraft, it is insufficient to complete the program in full and should be increased. At the same time, the company notes positive signals from the US Department of Defense.
The first phase of flight tests of the X-49A SpeedHawk began in June last year. Its purpose was to evaluate the design solutions that were supposed to allow the experimental helicopter to surpass the basic version of the SH-60F Seahawk in speed characteristics.
In tests carried out, the X-49A SpeedHawk demonstrated a 47 percent increase in speed with similar power ratings to the SH-60F, as well as half the vibration level. The helicopter's performance has been improved through the use of a tube-mounted Vectored Thrust Ducted Propeller (VTDP) tail rotor and wings that increase lift and reduce the load on the main rotor.
The immediate plans of the developers include the installation of a third engine on the X-49A SpeedHawk, as well as retractable landing gear and a fairing on the rotor hub to reduce the level of vibration.
It is planned that the cruising speed of serial helicopters will exceed 383 kilometers per hour, and the maximum speed is 415 kilometers per hour, while the SH-60F has the corresponding figures equal to 241 and 256 kilometers per hour. The unladen weight will increase by more than 700 kilograms, mainly due to the installation of a third engine. At the same time, the carrying capacity of the helicopter will increase by about 230 kilograms, and the combat range will expand almost threefold.
LTH:
Modification X-49
Main rotor diameter, m 16.36
Length, m 20.10
Height, m
Width, m
Weight, kg
empty plane 6900
maximum takeoff
Engine type 1 GTE General Electric T700-GE-701C
Power, kW 1 х 1210
Maximum speed, km / h 415
Cruising speed, km / h 383
Practical range, km
Practical ceiling, m
Crew, people 2
